I ran into this issue with CISCO VPN and VirtualBox where the VBox is unable to resolve DNS on the VPN of the host
$ VBoxManage list vms
⁃ “Data Stage Server” {e94cc386-9ab9-476c-8dfa-fa877ffa0c8c}
$ VBoxManage modifyvm “Data Stage Server” –natdnshostresolver1 on